The present invention relates to disposable absorbent articles, such as diapers, sanitary napkins, training pants, incontinent garments, overnight pads, panty liners, underarm shields, as well as other absorbent devices used for medical purposes, such as, surgical absorbents which utilize, to some degree, fluffed wood pulp fibers. Such articles are designed to absorb body fluids, such as urine, menses, blood, perspiration and other excrement discharged by the body. In order for such absorbent articles to function efficiently, the absorbent core must quickly absorb into the structure body fluids insulting its surface, retain the body fluid within the absorbent core and prevent body fluids from being discharged onto the person and/or the wearer's adjacent clothing.
The basic form of the absorbent article is well known and typically includes a bodyside, liquid-permeable cover, a garment-side, liquid-impermeable baffle and an absorbent core positioned between the cover and the baffle. Numerous variations of the elements in addition to the basic cover, baffle and absorbent core arrangement are known. Each additional element is usually directed to improving a specific characteristic of the absorbent article. Generally, on the larger absorbent articles, i.e. those designed to absorb and retain at least 20 grams of fluid, such as diapers, training pants, incontinent garments, overnight pads and maxi sanitary napkins, the absorbent core incorporates an absorbent batt that is used to absorb and retain the body fluids. This batt, sometimes referred to as "wadding", is composed of one or more layers of fluffed wood pulp and typically has a substantial thickness, that is, greater than about 5 millimeters. Advantageously, the fluffed wood pulp layer is quite soft, flexible, and comfortable. However fluffed wood pulp has a disadvantage of poor in-plane wicking ability. Since the fluid to be absorbed is usually deposited in a localized area within the absorbent batt the fluff wood pulp does not efficiently transport body fluids for effective utilization of absorbent article absorbent capacity.
Another disadvantage of the fluffed wood pulp is that it has a low wet resiliency or a low wet stability. This allows the batt to collapse when wet, exacerbating low in plane fluid distribution, enhancing the probability that the absorbent article will sag, clump-up, bunch, twist or rope. To overcome these disadvantages it is known in the absorbent art to incorporate into a fluffed wood pulp batt a moisture stable material such as a polymeric material. Although these polymeric materials provide a wet stability to the batt they are generally hydrophobic. To obtain a satisfactory wet stability it usually requires a substantial amount of the polymeric material, relative to the amount of pulp, be incorporated into the batt which impedes the fluid distribution and capacity of the fluffed wood pulp batt.
Improving the performance of a disposable absorbent article which utilizes a fluffed wood pulp absorbent batt continues to be a formidable undertaking, although a number of improvements have been made in both the materials used and its construction. Improving fluid handling performance and wet resiliency protection without compromising comfort and fit has not yet met the desired needs of the consumer.